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/* Filter driver - utility functions */
#include "inc.h"
#include <sys/mman.h>
#include <signal.h>
static clock_t next_alarm;
/*===========================================================================*
* flt_malloc *
*===========================================================================*/
char *flt_malloc(size_t size, char *sbuf, size_t ssize)
{
/* Allocate a buffer for 'size' bytes. If 'size' is equal to or less
* than 'ssize', return the static buffer 'sbuf', otherwise, use
* malloc() to allocate memory dynamically.
*/
char *p;
if (size <= ssize)
return sbuf;
if(!(p = alloc_contig(size, 0, NULL)))
panic("out of memory: %d", size);
return p;
}
/*===========================================================================*
* flt_free *
*===========================================================================*/
void flt_free(char *buf, size_t size, const char *sbuf)
{
/* Free a buffer previously allocated with flt_malloc().
*/
if(buf != sbuf)
free_contig(buf, size);
}
/*===========================================================================*
* flt_alarm *
*===========================================================================*/
clock_t flt_alarm(clock_t dt)
{
int r;
if((int) dt < 0)
return next_alarm;
r = sys_setalarm(dt, 0);
if(r != OK)
panic("sys_setalarm failed: %d", r);
if(dt == 0) {
if(!next_alarm)
panic("clearing unset alarm: %d", r);
next_alarm = 0;
} else {
if(next_alarm)
panic("overwriting alarm: %d", r);
next_alarm = getticks() + dt;
}
return next_alarm;
}
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